Unit 6 AP Bio Review

Semiconservative

half new, half old dna; half of original molecule is conserved in new molecule

dna replication difference in leading and lagging strand

DNA poly must build new stand in a 5’-3’ direction. DNA is antiparallel so one strand is built in the opposite direction of helicase (lagging) so it must catch up to the leading strand in fragments

DNA polymerase lll

builds new DNA strand

topoisomerase

relaxes supercoiled DNA

helicase

unzips DNA

ligase

joins okazaki fragments

RNA Primase

Adds RNA Primer

mRNA message

carries message from DNA to ribosome

tRNA transfer

transfers correct amino acid to growing protein

rRNA ribosome

structural component of ribosome

antisense

complementary/opposite to mRNA

exons

exit nucleus to be transcribed

introns

stay IN the nucleus and get recycled

Why can transcription and translation happen at the same time in prokaryotes and not eukaryotes?

mRNA must be processed before leaving the nucleus in eukaryotes, prokaryotes have no nucleus/processing

Initiation

ribosome binds to start codon (AUG)

Elongation

codons are read and AA’s are added to growing protein

termination

stop codon is reached, RNA detaches from ribosomes

Retroviruses

• has RNA which is reversed transcribed to DNA

• Reverse transcription makes many mistakes causing retroviruses to evolve quickly

regulatory sequence

activate or inhibit genes

histones

• tightly coiled DNA

• role: physically prevent transcription

benefit of gene expression in multicellular organisms

so cells can have different functions

benefit of gene expression of singular celled organisms

prevent waste or energy/resources

Effect of mutation in gene for lac operon not binding to operator

transcription could not be turned off

Effect of mutation in gene for lac operon not binding to lactose sugar

transcription permanently turned off

Reasons why gel electrophoresis machine might be used

1. Paternity tests

2. crime scene identification

Benefit of bacteria’s ability to be transformed to humans

can make humans proteins like insulin for medicine

Restriction Enzymes

cuts DNA bonds between the deoxyribose sugar and phosphate backbone

PCR

• heat separates DNA in many copies of small amount of DNA

• based on process of replication

Frameshift mutations

• ex: insertion and deletion

• bc they change the 3 nucleotide(codon) reading frame of the mRNA

lac operon

control whether or not bacteria produce lactase to break down lactose

RNA poly

moves along template in 3’-5’, builds RNa in 5’-3’ direction

DNA characteristics

• double strand

• deoxyribose (sugar)

• ATCG

• only in nucleus

RNA characteristics

• single strand

• ribose

• AUCG

• can survive in nucleus or cytoplasm